陶瓷滤管循环过程中残余粉尘层微观结构分析

Microstructure analysis of residual dust cake for ceramic filter during cycles

用陶瓷滤管微观结构分析方法考察过滤反吹循环过程中滤管表面残余粉尘层厚度、孔隙率、中位粒径等参数的变化规律,对残余粉尘层阻力随循环次数的变化进行分析计算。结果表明:由于滤管表面滤膜的微观结构参数分布不均,在循环初期存在严重的部分清灰现象;粉尘颗粒在滤膜内沉积,部分清灰现象得到改善,残余粉尘层的厚度分布趋于均匀;残余粉尘层内孔隙率分布差别较大,其中内层的孔隙率较低,并随着循环次数的增加不断降低,这导致滤管的残余压降不断增加。

The change laws of thickness,porosity,median particle diameter and other parameters of the residual dust cake on the ceramic filter surface after some cycles were measured by microstructure analysis method of the ceramic filter.The variation of the residual dust cake with the cycle times was analyzed.The results show that there exists a serious patch cleaning phenomenon in the initial period of the filtration cycle due to the uneven distribution of the microstructure parameters for the filter membrane.With the increase of cycle times,some dust particles deposit within the filter medium especially in some larger pores,which causes patch cleaning alleviate,and the thickness distribution of the residual dust cake become uniform.The porosity distributes non-uniformly along the residual dust cake depth and the inside one lower than the surface.With the cycle times increasing,the porosity of the part of residual dust cake near filter element decreases,which should be responsible for the residual pressure drop increasing.